The vacuum piping in a vacuum sewage system for a building or for a marine vessel can include quite a large piping network, which e.g. at connections, branches, traps and drains is subject to leakage, particularly during extended use. Furthermore, the sewage transported in the vacuum sewage system tends to form deposits and layers in the vacuum piping particularly due to the small diameter of the vacuum piping. The diameter of such vacuum piping in a vacuum sewage system is generally between 40 mm to 60 mm. Blockage or partial blockage may also occur due to various reasons, e.g. accumulated deposits or layers, or undesired material that has been discharged into the vacuum piping. Such blockages or partial blockages are detrimental, taking into account said small diameter of the vacuum sewage piping. In large piping networks the detection and localization of such problematic occurrences is difficult.
Various arrangements for monitoring leakage of vacuum sewage system are known. WO 02/50381 A1 discloses a system in which sewage is discharged by gravity from a building into an external collection tank from which sewage is separately and subsequently further transported by vacuum. The known system includes a control system for monitoring the failure of a vacuum valve through which sewage is discharged from the external collection tank into a vacuum piping based on monitoring excess running time of a vacuum pump. JP 3164750 B2 discloses a corresponding system where leakage of air into a vacuum system is detected by monitoring the flow-through and the running time of a vacuum pump. JP 4864513 B2 also discloses a corresponding system, in which leakage of the vacuum piping is monitored by several vacuum sensors. The known systems are limited only to leakage control.